87243 ÷ 4 = 21810 R3
We're going to perform division on 87243 with 4 as the divisor.

Step 1:
4 goes into 8 2 times with a remainder of 0.
Write down 2 as next digit of of the result. 
Result so far: 2
Subtract 8 from 8 to get 0.
Bring next digit (7) of the dividend behind the 0 and repeat the process: 7 / 4

Step 2:
4 goes into 7 1 times with a remainder of 3.
Write down 1 as next digit of of the result. 
Result so far: 21
Subtract 4 from 7 to get 3.
Bring next digit (2) of the dividend behind the 3 and repeat the process: 32 / 4

Step 3:
4 goes into 32 8 times with a remainder of 0.
Write down 8 as next digit of of the result. 
Result so far: 218
Subtract 32 from 32 to get 0.
Bring next digit (4) of the dividend behind the 0 and repeat the process: 4 / 4

Step 4:
4 goes into 4 1 times with a remainder of 0.
Write down 1 as next digit of of the result. 
Result so far: 2181
Subtract 4 from 4 to get 0.
Bring next digit (3) of the dividend behind the 0 and repeat the process: 3 / 4

Step 5:
4 goes into 3 0 times with a remainder of 3.
Write down 0 as next digit of of the result. 
Result so far: 21810
Subtract 0 from 3 to get 3.

The final result is 21810 with a remainder of 3.